Apparatuses for reducing metal residue in edge bead region from metal-containing resists

ABSTRACT

Apparatuses and methods are described for removing edge bead on a wafer associated with a resist coating comprising a metal containing resist compositions. The methods can comprise applying a first bead edge rinse solution along a wafer edge following spin coating of the wafer with the metal based resist composition, wherein the edge bead solution comprises an organic solvent and an additive comprising a carboxylic acid, an inorganic fluorinated acid, a tetraalkylammonium compound, or a mixture thereof. Alternatively or additionally, the methods can comprise applying a protective composition to the wafer prior to performing an edge bead rinse. The protective composition can be a sacrificial material or an anti-adhesion material and can be applied only to the wafer edge or across the entire wafer in the case of the protective composition. Corresponding apparatuses for processing the wafers using these methods are presented.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of copending U.S. patent applicationSer. No. 16/810,924 filed on Mar. 6, 2020 to Waller et al., entitled“Apparatuses for Reducing Metal Residue in Edge Bead Region fromMetal-Containing Resists,” which is a divisional of U.S. patentapplication Ser. No. 15/674,934 filed Aug. 11, 2017, now U.S. Pat. No.10,627,719, to Waller et al., entitled “Method of Reducing Metal Residuein Edge Bead Region from Metal Containing Resists,” which claimspriority to U.S. provisional patent applications 62/374,582 filed Aug.12, 2016 to Clark et al., entitled “Bead Washing for Metal Oxide BasedResists,” and 62/430,722 filed Dec. 6, 2016 to Cardineau et al.,entitled “Method of Reducing Metal Residue in Edge Bead Region fromMetal Containing Resists,” all of which are incorporated herein byreference.

FIELD OF THE INVENTION

The invention relates to processing to reduce metal contamination alongwafer edges potentially resulting from the use of metal based patterningresists.

BACKGROUND OF THE INVENTION

The processing of semiconductor circuits and devices has involved thecontinued shrinkage of critical dimensions over each generation. Asthese dimensions shrink, new materials and methods are required to meetthe demands of processing and patterning smaller and smaller features.Patterning generally involves selective exposure of a thin layer of aradiation sensitive material (resist) to form a pattern that is thentransferred into subsequent layers or functional materials. Promisingnew classes of metal based radiation resists especially suitable forproviding good absorption of extreme UV light and electron beamradiation, while simultaneously providing very high etch contrast havebeen discovered. To provide for commercialization of these new classesof resists, consideration of the process integration for the achievementof desired final products can be a significant step.

SUMMARY OF THE INVENTION

In a first aspect, the invention pertains to a method for removing edgebead on a wafer associated with a resist coating comprising a resistcomposition comprising metal, in which the method comprises the step ofapplying a first bead edge rinse solution along a wafer edge followingspin coating of the wafer with the resist composition. In someembodiments, the edge bead solution comprises an organic solvent and anadditive comprising a carboxylic acid, an inorganic fluorinated acid, atetraalkylammonium compound, or a mixture thereof.

In a further aspect, the invention pertains to a method for preparing awafer for radiation based patterning, in which the method comprisesapplying a protective composition to the wafer; spin coating a resistcomposition comprising metal after applying the protective composition;and performing edge bead rinse after spin coating the resist compositionthrough application of an edge bead rinse solution along the edge of thewafer.

In other aspects, the invention pertains to an apparatus comprising aspindle comprising a wafer support, a dispenser with a nozzle configuredto deposit fluid along an edge of a wafer mounted on the spindle, and areservoir of fluid configured to deliver the fluid to the nozzle fordispensing. Generally, the spindle is operably connected to a motorconfigured to rotate the spindle. In some embodiments, the fluidcomprises an organic solvent with an additive comprising a surfacemodification agent, an acidic compound, a tetraalkylammonium compound,or mixtures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematic perspective view of an edge bead rinse apparatusshown with a wafer positions for processing to perform an edge beadrinse.

FIG. 2 is a schematic diagram depositing steps to prepare a wafer with aresist layer following an edge bead rinse with two processing stepsshown.

FIG. 3 is a photograph of a microscope image depicting a wafer edgefollowing an edge bead rinse.

FIG. 4 is a schematic diagram depicting steps used to form a sacrificiallayer over a substrate that is then used to facilitate edge bead removalin a rinse step, in which insert A shows a top view of the final rinsedwafer.

FIG. 5 is a schematic diagram depicting steps used to form a sacrificialedge coating or sacrificial ring over a substrate that facilitates edgebead removal, in which insert A is a top view of the wafer with thesacrificial ring and insert B depicts the final bead edge rinsedstructure.

FIG. 6 is a schematic diagram depicting processing with an anti-adhesionedge coating to provide for substantial avoidance of resist depositionalong the edge and with a bead edge rinse to further reduce any residualmetal contamination along the edge following processing, in which insertA depicts a top view of the wafer with the anti-adhesion edge coating,insert B depicts a top view of the structure following resistdeposition, and insert C is a top view of the structure following anedge bead rinse.

DETAILED DESCRIPTION

Edge bead removal processes have been developed to more effectivelyremove metal and organometallic based resist materials and residues.Substrate edge resist build up can be removed prior to patterning asubstrate with radiation to reduce contamination of process equipmentwith resist material. Edge bead removal solutions designed fortraditional organic photoresists may not be sufficiently effective withthe removal of metal containing resists. Improved edge bead removalsolutions can use a selected solvent and may further contain anadditive, such as an acid, to facilitate the removal of resist build up.In additional or alternative embodiments, a sacrificial layer, e.g., apolymer layer, can be placed over the wafer edge or over the entirewafer surface to facilitate removal of resist from the bead edge.Furthermore, an anti-adhesion layer, e.g., a coating with a sufficientlylow critical surface tension, can be placed along the substrate edge toreduce or eliminate initial adherence of resist along the substrateedge. Due to the improved patterning abilities of metal-based resists,especially for fine patterning with extreme ultraviolet (EUV) light, itis advantageous to provide processing approaches that allow theeffective incorporation of metal-based resists into patterning processeswith the corresponding sophisticated equipment. Thus, the processing andcorresponding compositions described herein provide a significantcontribution to the commercialization of metal-based resists. As usedherein, substrate and wafer are used interchangeably unless statedotherwise to refer to structures generally but necessarily cylindricalin shape usually with a small thickness relative to dimensionsassociated with a planar extent. New rinse solutions are identified forprocessing of wafers coated with metal based or metal-containingpatterning resists to aid in the removal of edge beads. Resistcompositions comprising metal can generally be considered as comprisingmore than a contaminant amount of metal, such as at least 0.1 weightpercent metal, and some metal containing resist of particular interestare described further below. For the fine patterning of semiconductorsas well as for other radiation based lithographic processing, patterningresists are generally spin coated onto a wafer to form a relativelyuniform resist layer over most of the wafer surface. Spin coating canresult in a bead along the wafer edge with a buildup of resist relativeto the resist layer covering the majority of the wafer, even though someof the excess resist may spin off of the wafer surface. It is generallydesirable for the edge bead to be removed to facilitate processing ofthe wafer for patterning since the edge itself is not patterned usinglithography, and to reduce contamination. For the effective removal ofthe edge bead for metal-based or metal-containing resists, new rinsecompositions can comprise a suitable organic solvent and an additive,such as a carboxylic acid, an inorganic fluorinated acid, atetraalkylammonium fluoride with a strong acid, or a combinationthereof. Edge bead removal for metal based or metal-containing resistscan also be helpful to reduce undesirable residual metal following thepatterning process. After the bead edge rinse, patterning of the wafergenerally continues using usual steps for the patterning based on theresist.

During photoresist processing, an edge bead removal (EBR) rinse stepgenerally is used. EBR processing typically occurs prior to any thermalprocessing or baking following deposition of the photoresist andinvolves rinsing the peripheral edge of a wafer or substrate with asolvent to remove the photoresist in selected regions. This EBR processserves to reduce contamination of tools and machinery that handle ormanipulate the wafers or substrates. With the use of metal-basedphotoresists, reducing the residual amount of metal, e.g., tin, in theEBR region is desirable. Standard EBR solvents based on organic solventsdesigned for removing polymer resists may not be effective alone to adesirable degree at reducing the residual metal, e.g., tin,concentration on the edge region of the wafer surface to desired levels.Additionally, the methods and materials described herein may beadvantageous for processing resists containing a wide range of differentmetals, including Hf, Zr, In, Te, Sb, Ni, Co, Ti, W, Ta, Mo, andcombinations thereof, and such use is contemplated by the presentdisclosure.

The new class of radiation based resists can be based on metal oxidechemistry (metal oxo/hydroxo compositions) using radiation sensitiveligands to control stability and processability of the resists. A firstset of the new radiation based resists use peroxo ligands as theradiation sensitive stabilization ligands. Peroxo based metaloxo-hydroxo compounds are described, for example, in U.S. Pat. No.9,176,377B2 to Stowers et al., entitled “Patterned Inorganic Layers,Radiation Based Patterning Compositions and Corresponding Methods,”incorporated herein by reference. Related resist compounds are discussedin published U.S. patent application 2013/0224652A1 to Bass et al.,entitled “Metal Peroxo Compounds With Organic Co-ligands for ElectronBeam, Deep UV and Extreme UV Photoresist Applications,” incorporatedherein by reference. An effective type of resists have been developedwith alkyl ligands as described in U.S. Pat. No. 9,310,684B2 to Meyerset al., entitled “Organometallic Solution Based High ResolutionPatterning Compositions,” published U.S. patent application2016/0116839A1 to Meyers et al., entitled “Organometallic Solution BasedHigh Resolution Patterning Compositions and Corresponding Methods,” andU.S patent application Ser. No. 15/291738 entitled “Organotin OxideHydroxide Patterning Compositions, Precursors, and Patterning”, all ofwhich are incorporated herein by reference. Tin compositions areexemplified in these documents, and the data presented herein focuses ontin-based resists, although the Edge bead removal solutions describedherein are expected to be effective for other metal based resistsdescribed below.

With respect to the tin based resists of particular interest, theseresists are based on the chemistry of organometallic compositionsrepresented by the formula R_(z)SnO_((2−(z/2)−(x/2)))(OH)_(x) where0<z≤2 and 0<(z+x)≤4, in which R is a hydrocarbyl group with 1-31 carbonatoms. However, it has been found that at least some of the oxo/hydroxoligands can be formed following deposition based on in situ hydrolysisbased on compositions represented by the formula R_(n)SnX_(4−n) wheren=1 or 2, in which X is a ligand with a hydrolysable M—X bond. Ingeneral, suitable hydrolysable ligands (X in RSnX₃) may includealkynides RC≡C, alkoxides RO⁻, azides N₃ ⁻, carboxylates RCOO⁻, halidesand dialkylamides. Thus, in some embodiments all or a portion for theoxo-hydroxo compositions can be substituted with the Sn—X compositionsor a mixture thereof The R—Sn bonds generally are radiation sensitiveand form the basis for the radiation processable aspect of the resist.But some of the R_(z)SnO_((2−(z/2)−(z/2)))(OH)_(x) composition can besubstituted with MO_(((m/2)−1/2))(OH)₁ where 0<z≤2, 0<(z+w)≤4, m =formalvalence of M^(m+), 0≤1≤m, y/z=(0.05 to 0.6), and M=M′ or Sn, where M′ isa non-tin metal of groups 2-16 of the periodic table, and R ishydrocarbyl groups with 1-31 carbon atoms. Thus the resist beingprocessed during the edge bead rinse can comprise a selected blend ofR_(z)SnO_((2−(z/2)−(x/2)))(OH)_(x) , R′_(n)SnX_(4−n), and/orMO_(((m/2)−1/2))(OH)₁, in which generally a significant fraction of thecomposition includes alkyl-tin bonds. Other resist compositions include,for example, compositions having metal carboxylate bonds (e.g., ligandsof acetate, propanoate, butanoate, benzoate, and/or the like), such asdibutyltin diacetate.

While metal oxo/hydroxo or carboxylate based resists referenced aboveare particularly desirable, some other high performance resists may besuitable in some embodiments. Specifically, other metal-based resistsinclude those with high etch selectivity to the template, fill material,and buffer hardmask. These may include resists such as metal-oxidenanoparticle resists (e.g., Jiang, Jing; Chakrabarty, Souvik; Yu, Mufei;et al., “Metal Oxide Nanoparticle Photoresists for EUV Patterning”,Journal Of Photopolymer Science And Technology 27(5), 663-666 2014,incorporated herein by reference), or other metal containing resists (APlatinum-Fullerene Complex for Patterning Metal ContainingNanostructures, D. X. Yang, A. Frommhold, D. S. He, Z. Y. Li, R. E.Palmer, M. A. Lebedeva, T. W. Chamberlain, A. N. Khlobystov, A. P. G.Robinson, Proc SPIE Advanced Lithography, 2014, incorporated herein byreference). Other metal-based resists are described in published U.S.patent application 2009/0155546A1 to Yamashita et al., entitled“Film-Forming Composition, Method for Pattern Formation, andThree-Dimensional Mold,” and U.S. Pat. No. 6,566,276 to Maloney et al.,entitled “Method of Making Electronic Materials,” both of which areincorporated herein by reference.

In electronics processing, it is generally desirable to mitigate tracemetal contamination, so with the use of organometallic based resists, itis desirable to remove tin and/or other metal residue potentiallyresulting from the resists. The improved edge bead removal solutionsgenerally comprise an organic solvent and one or more additives wherethe additives can improve the metal removal. Suitable additives include,for example, organic acids, inorganic fluoroacids, tetraalkylammoniumhalides, and mixtures thereof. Suitable additives may also function ascomplexing or chelating agents such as carboxylates, dicarboxylates,halides, phosphates, phosphonates, sulfates, sulfonates, and mixturesthereof. The additives may also function as surfactants and/or chelatingagents. Thus, the conjugate anions of the various acids listed hereincan be added as chelating agents. Also, surfactants, such as Triton™-X,a non-ionic surfactant, can also be used as additives. The additives canbe selected to be soluble in the organic solvent. The solutions cancomprise additive from about 0.1 wt % to about 25 wt %, in furtherembodiments from about 0.2 wt % to about 20 wt % and in additionalembodiments from about 0.25 wt % to about 20 wt %. A person of ordinaryskill in the art will recognize that additional ranges of additiveconcentrations within the explicit ranges above are contemplated and arewithin the present disclosure. Suitable organic solvents include, forexample, glycol ethers and esters thereof, such as propylene glycolmethyl ether (PGME), propylene glycol methyl ether acetate (PGMEA),propylene glycol butyl ether (PGBE), ethylene glycol methyl ether,and/or the like; alcohols, such as ethanol, propanol, isopropyl alcohol,isobutyl alcohol, hexanol, ethylene glycol, propylene glycol, and/or thelike; cyclic esters, such as gamma-butyrolactone; esters, such asn-butyl acetate, ether acetate, or the like, and/or mixtures thereof;ketones, such as heptanone, and/or the like; liquid cyclic carbonates,such as propylene carbonate, butylene carbonate, and/or the like; andany mixtures thereof. A blended solvent with about 50 to about 90 wt %PGMEA, about 1 wt % to about 20 wt % PGME, about 1 wt % to about 10 wt %y-buryrolactone and about 1 wt % to about 20 wt % n-butyl acetate hasbeen proposed as a desirable EBR solution with desirable rheology andevaporation properties in U.S. Pat. No. 8,227,182 to Lee et al.,entitled “Methods of Forming a Photosensitive Film,” incorporated hereinby reference. Suitable organic acids include, for example, carboxylicacids, such as acetic acid, citric acid, oxalic acid,2-nitrophenylacetic acid, 2-ethylhexanoic acid, dodecanoic acid, and/orthe like; sugar acids, such as ascorbic acid, tartaric acid, glucuronicacid, and/or the like; sulfonic acids, such as benzene sulfonic acid,p-toluenesulphonic acid, and/or the like; phosphate esters andphosphoric acids, such as bis(2-ethylhexyl) phosphoric acid;hydrofluoric acid (HF); sulfuric acid (H₂SO₄); and any mixtures thereof.Suitable inorganic fluoroacids include, for example, hexafluorosilicicacid, hexafluorophosphoric acid, fluoroboric acid and/or the like.Suitable tetraalkylammonium compounds include, for example,tetramethylammonium fluoride, tetrabutylammonium fluoride,tetrabutylammonium fluorosilicate, and/or the like, or mixtures thereof.

Multiple rinse steps can be performed to achieve desired levels of edgecleaning. In some embodiments, an edge rinse can be performed once,twice, three times, four times, five times, six times, ten times, ormore than ten times with the same solution to achieve desired metalreduction. Furthermore, two different rinse solutions can be appliedduring an edge bead rinse process. Each different solution can beselected independently from the solutions described above. For wafersgenerally having diameters from about 3 inches to about 18 inches,during each application solution can be delivered in quantities fromabout 0.05 milliliter (mL) to about 50 mL, in further embodiments fromabout 0.075 mL to about 40 mL, and in other embodiments form about 0.1mL to about 25 mL. In some embodiments, the solution can be sprayed at aflow rate from about 5 mL/min to about 50 mL/min, and the solution canbe applied for from about 1 second to about 5 minutes and in furtherembodiments from about 5 seconds to about 2 minutes. A person ofordinary skill in the art will recognize that additional ranges ofsolution application numbers and volumes within the explicit rangesabove are contemplated and are within the present disclosure.

An apparatus to perform edge bead removal is shown in FIG. 1. Referringto FIG. 1, a wafer processing apparatus 100 comprises a spindle 102 witha hollow core 104 connected to a motor to rotate the spindle and a pumpconfigured to apply negative pressure to the hollow core of the spindle,a chuck 106 operably connected to the spindle to rotate with thespindle, and a fluid dispenser 108 configured to dispense fluid 110 tothe edge of one or both surfaces of a wafer supported on chuck 106 andheld in place by negative pressure within hollow core 104. A wafer 112is shown in FIG. 1 appropriately positioned in the apparatus. Fluiddispenser 108 can comprise a nozzle or the like to direct fluid to thewafer. A reservoir 114 is operably connected to fluid dispenser 108 toprovide the fluid. Reservoir can be a suitable container for holding thefluid connected with a tubing, a hose, or the like, and gravity or apump or the like can be used to drive the fluid transfer from reservoir114. Negative pressure applied to hollow core 104 can be provided by anegative pressure device 116, which can be a pump, aspirator, blower orthe like. Spindle 102 can also be connected to a motor 118, which canhave an appropriate design and fittings, to spin spindle 102 for waferprocessing. A specific equipment design for edge bead processing isdescribed in U.S. Pat. No. 8,826,926 B2 to Chalom et al., entitled“Methods of Profiling Edges and Removing Edge Beads,” incorporatedherein by reference.

The edge bead rinse process is schematically shown in FIG. 2. As shownin the left image, substrate 120 is obtained and is coated 122 withmetal-based resist 124. Then, a bead edge rinse step 126 is performed toremove resist along edge 128 of substrate 120 to form edged resist layer130. The edge bead rinse process is described further above in terms ofcompositions, quantities of compositions and delivery apparatuses. Theresulting structure 132 with edged resist layer 130 can then be used toa patterning step for substrate 120. The coating of the wafer with aresist, for example, can be performed by depositing from about 0.25 mLto about 20 mL of resist solution onto a stationary wafer in anappropriate configuration, and then spinning the wafer to spread theresist, for example, from 250 rpm to 10,000 rpm for a time from about 5seconds (s) to about 15 minutes (mins). Spin speed can be varied overthe spin time if desired. A person of ordinary skill in the art willrecognize that additional ranges of fluid quantities, spin rates andspin times within the explicit ranges above are contemplated and arewithin the present disclosure.

To perform a rinse step, the wafer generally can be spun at a low tomoderate rate during the fluid deposition and then spun at a greaterrate following fluid deposition. The edge bead rinse solution can beapplied to the edge as well as the back of the wafer. For example, thewafer can be spun during fluid deposition at from 5 rpm to 10,000 rpmand in further embodiments from 50 rpm to 5000 rpm. The liquiddeposition process can be performed from 1 second to 5 minutes and infurther embodiments from about 5 seconds to about 3 minutes. Followingliquid deposition, the wafer can be spun at a rate of at least 500 rpmand in further embodiments from 750 rpm to 6000 rpm, and the post liquiddeposition spin can be performed for from 2 seconds to 10 minutes and infurther embodiments from 5 seconds to about 5 minutes. Spin speed can bevaried over the spin time if desired. A person or ordinary skill in theart will recognize that additional ranges of spin speed and spin timeswithin the explicit ranges above are contemplated and are within thepresent disclosure. Following the post deposition spin, a subsequentrinse step can be performed, and this processing can be repeated asselected.

Following application of an edge bead solution to remove the edge bead,the edge of a wafer can look visibly clean to inspection as shown inFIG. 3 with a clean edge 134. As described above, the edge bead rinseprocesses can comprise a plurality of rinsing steps with the same and/ordistinct rinsing solutions to achieve the desired results. To fullyevaluate the removal of metal, the wafer can be examined for residualmetal. A suitable approach available commercially for the evaluation oftrace metals generally involves Inductively Coupled Plasma MassSpectrometry (ICP-MS). For evaluation of a silicon wafer surface, avariation of this analytical technique termed Vapor PhaseDecomposition-Inductively Coupled Plasma Mass Spectrometry (VPD-ICP-MS)can be used. Using this technique, the residual metal can be determinedper unit area of the wafer surface along the edge. For the tin basedresists described in the example, it is desirable to obtain residual tinin amounts of no more than about 100×10¹⁰ atoms/cm² of wafer area, infurther embodiments no more than about 25×10¹⁰ atoms/cm², and inadditional embodiments no more than about 10×10¹⁰ atoms/cm² based onwafer area in the rinsed region. A person of ordinary skill in the artwill recognize that additional ranges of residual tin within theexplicit ranges above are contemplated and are within the presentdisclosure.

In addition to the use of improved EBR solutions as described above, acoating along the substrate edge or across the whole substrate can beapplied to further facilitate the reduction of residual metal along thewafer edge after an EBR process. Such coatings are generally insolublein the photoresist coating solution and may or may not be completely orsubstantially removed as part of subsequent EBR processes. After thecoatings are applied, the resist solution can be deposited that may ormay not cover the coatings, as described further below. In someembodiments, suitable coatings can be a sacrificial material, such aspolystyrene or amorphous carbon, that may or may not cover the entiresubstrate and may or may not be selectively removed with the resistcoating during subsequent EBR processing. If the coating covers theentire wafer, the remaining coating, such as in the case of amorphouscarbon, can be used as a differentially etchable layer in the patterningstack. In other embodiments, a suitable polymer coating, such aspolystyrene, can be coated along only the periphery of a wafer and canbe removed at least in part in subsequent EBR processing. In this case,the coating can be removed with the EBR processing of the resistmaterial or it can alternately be removed by a separate EBR process. Inother embodiments, suitable coatings, such as a surface modifying layeror an anti-adherence coating, can cover only the peripheral edge of awafer to prevent the resist solution from adhering to the surface of thecoating during resist deposition, and may or may not be removed insubsequent EBR processing,

Thus, improved processing can pertain to coating the edge surface regionor entire surface of the wafer with a secondary sacrificial materialprior to coating the metal-based resist. In additional or alternativeembodiments, improved processing can comprise coating the wafer edgesurface region with a surface treatment layer which prevents wetting ofthe edge surface region with resist precursor solution. Generally,neither a sacrificial layer nor an anti-adhesion layer require a bakingstep prior to resist coating and EBR, providing for a desirable processflow. Without wanting to be limited by theory, it is presumed thatanti-adhesion materials and processes inhibit adhesion ofmetal-containing species to the substrate surface, thus facilitatingmore complete removal of the photoresist with reduced metal residue whenappropriate EBR solvents or mixtures are applied. Improved rinsesolutions described herein have proven particularly effective atremoving residual tin atoms, and may be used as a stand-alone EBRsolution, or in combination with the sacrificial or surface treatmentlayers described herein. As illustrated by the materials and methods inthe Examples, residual tin levels after an EBR process can be reduced toacceptable levels using the methods described herein.

The selection of compositions for a sacrificial material can beinfluence by whether or not the coating covers the entiresubstrate/wafer of just the edge. In general, the sacrificial materialmay or may not be fully removed during the bead edge rinse as long asthe presence of the sacrificial material favors removal of metal ionsfrom along the bead edge. If the sacrificial layer covers the wafer, asacrificial layer may also be removable when corresponding resist isremoved with or without irradiation. Specifically, the sacrificialmaterial can be selected for removal using the developer for the resist.Additionally or alternatively, a sacrificial layer such as an amorphouscarbon layer or a spin-on carbon layer can be removed during an etchstep on the wafer/substrate material. Spin-on-carbon material isavailable commercially from JSR Corp. (Japan). See also, for example,U.S. Pat. No. 9,102,129B2 to Krishnamurthy et al., entitled “Spin-onCarbon Compositions for Lithographic Processing,” incorporated herein byreference. The spin on carbon materials can be coated using anappropriate coating process and can be dried for example with heating.CVD carbon layer deposition is described, for example, in published U.S.patent application 2007/0037014 to Nagata, entitled “Method of Forming aProtective Film and a Magnetic Recording Medium Having a Protective FilmFormed by the Method,” incorporated herein by reference. A sacrificialcoating that modifies the surface edge of the substrate in the absenceof heating or other post-processing are described that allow for removalof tin based resists along with the edge portion of the protectivecoating during an EBR process. A specific example is described belowusing polystyrene as an edge coating for use with the tin based resist.

Processing to cover a substrate with a sacrificial material over theentire substrate is outlined in FIG. 4. After a substrate 150 isobtained, a layer of sacrificial material is applied 152 over substrate150 to form sacrificial layer 154. Application of sacrificial layer 154can be performed using an appropriate coating solution as describedabove using spin coating, spray coating, knife edge coating, chemicalvapor deposition (CVD), for example, for the deposition of amorphouscarbon, or other suitable coating technique, or combinations thereof.Then, a resist precursor solution can be deposited 156 to form a resistlayer 158. Resist precursor solutions are generally applied by spincoating, but spray coating or other coating processes can be used. Afterforming resist layer 158, an edge bead rinse step 160 can be performedto form edged structure 162 with an edged sacrificial layer 164 and anedged resist layer 166. The edge bead rinse process is described furtherabove and can be similarly employed in the context of the processing inFIG. 4. A top view of edged structure 162 is shown in insert A of FIG.4.

The processing to cover the substrate with a sacrificial material canfollow the procedure used to deposit a resist. The precursor solutionfor the sacrificial material can be deposited on a stationary wafer atappropriate coverage. Then, the wafer can be spun to distribute thefluid over the wafer surface. A quantity of fluid can be selected basedon the concentration, fluid properties, such as viscosity, desiredthickness of the dried sacrificial material, and other relevantparameters with adjustment based on empirical evaluation. Generally, thequantity of fluid can be from about 0.1 mL to about 100 mL and infurther embodiments from about 0.25 mL to about 25 mL. After depositionof the fluid, to spread the fluid the wafer can be spun to distributethe fluid over the wafer, in which the wafer can be spun at from 250 rpmto 10,000 rpm and in further embodiments from 450 rpm to 6000 rpm for atime from 2 s to 10 mins and in further embodiments from 5 s to 5 mins.Spin speed can be varied over the spin time if desired. To achievedesired coating, a plurality of deposition and spin steps can be used ifdesired. A person of ordinary skill in the art will recognize thatadditional ranges of fluid quantities, spin speeds and spin times withinthe explicit ranges above are contemplated and are within the presentdisclosure.

The use of a sacrificial layer along an edge is depicted schematicallyin FIG. 5. After obtaining a substrate 180, sacrificial layer coatingmaterial can be applied 182 along the edge of substrate 180 to form edgeprotected structure 184 with sacrificial ring 186 on substrate 180.Application of the sacrificial layer coating material can be performedalong the edge, for example, using a bead rinse device modified todeliver the coating material along the edge. During the delivery of thecoating material, the substrate can be spun at a rate that is consistentwith maintenance of at least a significant fraction of the coatingmaterial along the edge. A top view of edge protected structure 184 isshown in insert A of FIG. 5. Then, a resist solution can be deposited188 over edge protected structure 184 to form resist layer 190. Edgebead rinse process 192 then removes both sacrificial ring 186 and theresist material along the edge to form edged structure 194 with edgedresist layer 196 on substrate 180. The edge bead rinse process isdescribed further above and can be similarly employed in the context ofthe processing in FIG. 5. A top view of edged structure 194 is shown inFIG. 5.

An alternative approach to provide a clean bead edge involves applyingan edge coating surface treatment that inhibits surface build-up ofresist along the edge. In particular, an edge coating composition can beapplied that has a critical surface tension that is below the surfacetension of the resist coating composition. The critical surface tension(CST) is a property of a solid surface. Most inorganic solids, such as asurface of a silicon wafer, are hard and have a correspondingly highcritical surface tension. Therefore, most liquids wet a silicon wafer.Coatings can be applied that have a lower surface tension, such assilanes or fluorinated compounds, as a surface treatment that functionsas an anti-adhesion coating along the wafer edge. An anti-adhesioncoating can be applied over the wafer edge prior to application of theresist. When the resist is applied, the resist substantially does notstick along the edge. A bead edge rinse then is performed following theapplication of the resist to remove any minor amounts of resist that mayhave remained along the edge. After the bead edge rinse, processing iscontinued as usual. Since the edge is not patterned, the anti-adhesioncoating along the edge does not need to be removed or to be processableduring patterning processes for the wafer.

Suitable anti-adhesion compositions include, for example, fluoronatedvinyl polymers, such as polytetrafluoroethylene and copolymers thereof.The fluoropolymers may or may not be fully fluorinated, i.e.perfluoro-polymers. Alkyl halogenated silanes can also be useful tosupply a lower critical surface tension anti-adhesion surface. Suitablesilanes include, for example, alkyltrichlorosilanes, such asheneicosafluorododecyltrichlorosilane (CST≈6-7 dynes/cm at 25° C.),heptadecylfluorodecyltrichlorosilane (CST≈12 dynes/cm at 25° C.),octadecyltrichloro silane (CST≈20-24 dynes/cm at 25° C.). For resistswith somewhat higher surface tensions, alkyltrialkoxysilanes can alsoprovide sufficient anti-adhesion properties. Suitablealkyltrialkoxysilanes include, for example, methyltrimethoxysilane(CST≈22.5 dynes/cm at 25° C.), nonafluorohexyltrimethoxysilanes (CST≈23dynes/cm at 25° C.), or mixtures thereof. An exemplified alkyltinoxyhydroxy based resist exemplified herein had a surface tension ofabout 23 dynes/cm at 25° C. The selection of the anti-adhesion coatingmaterials generally can be influenced by the composition of the resist,but the coating compositions generally have a critical surface tensionat 25° C. of no more than about 50 dynes/cm, in further embodiments nomore than about 30 dynes/cm and in further embodiments no more thanabout 22 dynes/cm. A person of ordinary skill in the art will recognizethat additional ranges of critical surface tension within the explicitranges above are contemplated and are within the present disclosure.

The fluoropolymers can be dispensed, for example, as a dispersion ofpolymer microparticles. The dispersant liquid can be a fluorinatedalkane, such as perfluorohexane, perfluorooctane, or the like, ormixtures thereof. The silanes can be dispensed in a suitable solvent,such as methylene chloride, tetrahydrofuran (THF), toluene, or othersuitable organic solvents or mixtures thereof.

The application of an anti-adhesion coating along the substrate edge isshown schematically in FIG. 6. After obtaining a substrate 210, asolution of surface modifying material is applied 212 to form edgeprotected structure 214 with an anti-adhesion edge coating 216 alongsubstrate 210. Application of surface modifying material to formanti-adhesion edge coating 216 can be performed, for example, with anedge bead rinse apparatus modified to deliver the material undersuitable conditions to allow a significant amount of the coatingmaterial to remain on the substrate edge. A top view of edge protectedstructure 214 is shown in insert A of FIG. 6. Then, resist precursorsolution is deposited 218 onto edge protected structure 214 to form anedged resist layer 220. Application of resist precursor solution can beperformed using spin coating, spray coating or other suitabletechnique(s). A top view of the structure with edged resist layer 220 isshown in insert B of FIG. 6. An edge bead rinse is then performed 222 toremove any residual resist along the edge, and optionally also removeall or a portion of anti-adhesion edge coating 216, to form rinsedstructure 224 with rinsed edge 226 which may or may not include residualanti-adhesion edge coating. The edge bead rinse is performed asdescribed above. A top view of rinsed structure 224 is shown in insert Cof FIG. 6.

With respect to the application of a sacrificial coating along the waferedge as outlined in FIG. 5 or the application of a surface modifyingcomposition as outlined in FIG. 6, the wafer generally can be spun at alow to moderate rate during the fluid deposition and then spun at agreater rate following fluid deposition. For example, the wafer can bespun during fluid deposition at from 5 rpm to 500 rpm and in furtherembodiments from 10 rpm to 250 rpm. The liquid deposition process can beperformed from 5 seconds to 5 minutes and in further embodiments fromabout 15 seconds to about 3 minutes. Following liquid deposition, thewafer can be spun at a rate of at least 500 rpm and in furtherembodiments from 750 rpm to 4000 rpm, and the post liquid depositionspin can be performed for from 5 seconds to 10 minutes and in furtherembodiments from 10 seconds to about 5 minutes. Spin speed can be variedover the spin time if desired. A person or ordinary skill in the artwill recognize that additional ranges of spin speed and spin timeswithin the explicit ranges above are contemplated and are within thepresent disclosure. Following the post deposition spin, a subsequentrinse step can be performed, and this processing can be repeated asselected.

Generally, with respect to surface modification coatings (e.g.,sacrificial coatings or anti-adhesion coatings) either along the edge orover the wafer surface, a coating following drying can be in someembodiments no more than about 10 microns thick, in some embodiments nomore than about 5 microns thick and in further embodiments no more thanabout 1 microns thick. In additional or alternative embodiments, athinner coating can be desirable for example from about 1 nm to about500 nm, in further embodiments from about 5 nm to about 250 nm, and inother embodiments from about 7 nm to about 100 nm. A person of ordinaryskill in the art will recognize that additional ranges within theexplicit thickness ranges above are contemplated and are within thepresent disclosure. The concentrations and wet coating thicknesses canboth be adjusted to achieve desired thickness of the coatings.

In all embodiments, those skilled in the art will recognize that theidentity of the substrate is not limited except by reasonableconstraints recognized by those of ordinary skill in the art, such as asize that is compatible with process equipment and sufficient mechanicalstrength to tolerate processing. Suitable substrate surfaces cancomprise silicon, such as single crystalline silicon, polycrystallinesilicon, amorphous silicon, or the like, ceramics, such as siliconoxide, titanium oxide or the like, or other suitable materials orcombinations thereof. The substrate surface may or may not be alreadypatterned prior to initiation of the further patterning process of whichthe EBR processing is a part of the specific patterning step.

EXAMPLES Example 1 Selected EBR Solvents and Carboxylic Acid Additives

This example demonstrates the effectiveness of organic solvents withcarboxylic acid additives for performing effective residue removal withtin based radiation patternable resists.

Experiments were performed with two different radiation patternableresists. R1 resist comprised organometallic tin oxyhydroxide resist witha mixture of two distinct alkyl ligands, and R2 resist comprised amixture of an organometallic tin oxyhydroxide resist with an alkylligand and a tin oxyhydroxide composition without alkyl ligands. Theresists were deposited via spin coating onto single crystal siliconwafers. Immediately following the deposition of the resist, the waferwas set to rotate at 50 rpm while 5 mL of a rinse solution was dispensedonto the wafer so as to cover its entire surface. Immediately afterdispensing of the rinse solution, the wafer was spun at 1500 rpm for 45seconds until dry. In some cases, as indicated in Table 1, a seconddistinct rinse solution was dispensed onto the wafer subsequent to spindrying of the first rinse solution, and was processed in an identicalmanner, i.e., dispensed onto the wafer while rotating at 50 rpm,followed by spinning at 1500 rpm for 45 seconds to dry. If appropriate,immediately after this higher speed spin, a next volume of rinsesolution was dispensed and the procedure was repeated as above,typically 5 times, until after the higher speed spin following the finalrinse solution application. It is believed that the residue removalevaluated in these tests will approximate the effectiveness of an edgebead rinse process in which only the wafer edge is rinsed.

Measurements of residual metal was performed by ChemTrace®, using VaporPhase Decomposition-Inductively Coupled Plasma-Mass Spectrometry(VPD-ICP-MS) of the bevel edge. Results in Tables 1 and 2 were obtainedwith resist R1, and results in Table 3 were obtained with resist R2. Toobtain the results in Table 1, a total of 5 rinse steps were performedwith 5 ml per rinse step and a drying spin between each rinse step. InTables 2 and 3 “n×a mL”, such as 4×3 mL, indicate multiple rinse stepsof a specified volume with the same solution, so 4×3 mL would indicate 4rinse steps each using 3 mL of solution. Table 4 provides a list ofsolvents and additives used in the previous Tables. As the results show,R2 provide a more significant challenge with respect to desired removalof tin, but desirable results were obtained with suitable rinsesolutions. However, for both resist, rinse solutions with additives weresuccessful in reducing

TABLE 1 1- or 2- VDP-ICP stage EBR Result Sn Wafer strip? Strip ProcessDescription (E10 atom/cm²) 1 n/a (Blank wafer for control) 9.1 2 1Solvent 1 3600 3 1 Solvent 2 3100 4 1 Solvent 3 1400 5 2 1) Solvent 1,2) Solvent 2 3200 6 1 Solvent 1 + Additive 1 270 7 2 1) Solvent 1, 2)Solvent 2 + 540 Additive 1 8 1 Solvent 2 + Additive 1 620 9 2 1) Solvent1, 2) Solvent 2 + 120 Additive 2 10 1 Solvent 3 + Additive 3 19 11 2 1)Solvent 1, 2) Solvent 3 850 12 2 1) Solvent 1, 2) Solvent 3 + 8.9Additive 3

TABLE 2 1-or 2- stage EBR VDP-ICP Result Sn Wafer strip? Strip ProcessDescription (E10 atom/cm²) 13 1 (4 × 3 mL) Solvent 1 527 14 1 (4 × 3 mL)Solvent 2 + 5 wt % Additive 1 24 15 1 (5 × 5 mL) Solvent 2 + 5 wt %Additive 1 8.6 16 2 (5 × 5 mL) 1) Solvent 1, 0.27 (4 × 5 mL) 2) Solvent2 + 5 wt % Additive 2 17 2 (5 × 5 mL) 1) Solvent 1, 9.4 (4 × 5 mL) 2)Solvent 2 + 5 wt % Additive 4 18 2 (5 × 5 mL) 1) Solvent 1, 15 (4 × 5mL) 2) Solvent 2 + 2 wt % Additive 5 19 2 (5 × 5 mL) 1) Solvent 2, 6.3(4 × 5 mL) 2) Solvent 1 + 2 wt % Additive 6 20 2 (5 × 5 mL) 1) Solvent1, 7.8 (4 × 5 mL) 2) Solvent 2 + 5 wt % Additive 4 21 2 (5 × 5 mL) 1)Solvent 1, 17 (4 × 5 mL) 2) Solvent 2 + 2 wt % Additive 5 22 1 (10 × 5mL) Solvent 2 + 5 wt % Additive 1 18 23 1 (5 × 5 mL) Solvent 3 70 24 2(5 × 5 mL) 1) Solvent 3, 12 (4 × 5 mL) 2) Solvent 2 + 5 wt % Additive 125 2 (5 × 5 mL) 1) Solvent 3, ND (4 × 5 mL) 2) Solvent 2 + 5 wt %Additive 2 26 1 (5 × 5 mL) Solvent 3 + 5 wt % Additive 1 18 27 1 (5 × 5mL) Solvent 2 + 2.5 wt % Additive 1 + 2.5 32 wt % Additive 2 28 1 (5 × 5mL) Solvent 2 + 1.5 wt % Additive 1 + 1.5 18 wt % Additive 2 + 1.5 wt %Additive 6 29 1 (5 × 5 mL) Solvent 2 + 2.5 wt % Additive 1 + 2.5 33 wt %Additive 6 30 2 (5 × 5 mL) 1) Solvent 2 + 2.5 wt % Additive 1 + 30 2.5wt % Additive 6, (1 × 5 mL) 2) Solvent 3 31 1 (5 × 5 mL) Solvent 3 + 5wt % Additive 3 ND 32 1 (5 × 5 mL) Solvent 3 + 1 wt % Additive 2 17 33 1(5 × 5 mL) Solvent 3 + 3.5 wt % Additive 3 22 34 1 (5 × 5 mL) Solvent3 + 5 wt % Additive 3 4

TABLE 3 1- or 2- stage EBR VDP-ICP Result Sn Wafer strip? Strip ProcessDescription (E10 atom/cm²) 35 1 (5 × 5 mL) Solvent 1 + 5 wt % Additive 315 36 1 (5 × 5 mL) Solvent 3 15000 37 1 (5 × 5 mL)Solvent 1 18000 38 1(5 × 5 mL) Solvent 1 + 05. wt % Additive 3 179 39 1 (5 × 5 mL) Solvent4 + 5 wt % Additive 1 3200 40 1 (5 × 5 mL) Solvent 4 17000 41 1 (5 × 5mL) Solvent 1 + 10 wt % Additive 1 1700 42 1 Solvent 1 21000 43 2 (5 × 5mL) 1) Solvent 3 + 5 wt % Additive 3, 460 (1 × 5 mL) 2) Solvent 3 44 1Solvent 3 7700 45 2 (5 × 5 mL) 1) 1) 78 wt % solvent 6 + 10 wt % 35solvent 5 + 10 wt % Additive 3 + 2 wt % Additive 7, (1 × 5 mL) 2)Solvent 1 46 2 (5 × 5 mL) 1) 1) 78 wt % solvent 6 + 10 wt % 58 solvent5 + 10 wt % Additive 3 + 2 wt % Additive 7, (1 × 5 mL) 2) Solvent 1 47 2(5 × 5 mL) 1) 1) 78 wt % solvent 6 + 10 wt % 33 solvent 5 + 10 wt %Additive 3 + 2 wt % Additive 7, (1 × 5 mL) 2) Solvent 1 48 1 (1 × 5 mL)80 wt % Solvent 6 + 10 wt % Solvent 160 5 + 5 wt % Additive 3 + 5 wt %Additive 8 49 1 (1 × 5 mL) 75 wt % Solvent 6 + 10 wt % Solvent 170 5 +10 wt % Additive 9 + 5 wt % Additive 3 50 1 (1 × 5 mL) 85 wt % Solvent7 + 10 wt % Additive 150 9 + 5 wt % Additive 3 51 1 (1 × 5 mL) 80 wt %Solvent 7 + 10 wt % Additive 79 9 + 10 wt % Additive 3 52 1 (1 × 5 mL)95 wt % Solvent 7 + 5 wt % Additive 3 97 53 1 (1 × 5 mL) 85 wt % Solvent6 + 10 wt % Solvent 95 5 + 5 wt % Additive 3 54 1 (1 × 5 mL) 83 wt %Solvent 6 + 10 wt % Solvent 54 5 + 5 wt % Additive 3 + 2 wt % Additive 755 1 (1 × 5 mL) 83 wt % Solvent 6 + 10 wt % Solvent 86 5 + 5 wt %Additive 3 + 2 wt % Additive 10 56 1 (1 × 5 mL) 88 wt % Solvent 6 + 10wt % Solvent 630 5 + 2 wt % Additive 7 57 1 (1 × 5 mL) 88 wt % Solvent6 + 10 wt % Solvent 3200 5 + 2 wt % Additive 10 58 1 (1 × 5 mL) Solvent8 + 0.5 wt % Additive 3 2100 59 1 (1 × 5 mL) Solvent 8 + 1 wt % Additive3 260 60 1 (1 × 5 mL) Solvent 8 + 5 wt % Additive 3 43 61 1 (1 × 5 mL)Solvent 8 + 10 wt % Additive 3 22 62 1 (1 × 5 mL) Solvent 8 + 20 wt %Additive 3 51 63 1 (1 × 5 mL) 85 wt % Solvent 6 + 10 wt % Solvent 4805 + 5 wt % Additive 11 64 1 (1 × 5 mL) 85 wt % Solvent 6 + 10 wt %Solvent 99 5 + 5 wt % Additive 8 65 1 (1 × 5 mL) Solvent 5 + 85 wt %Additive 9 300 66 1 (1 × 5 mL) 50 wt % Solvent 6 + 50 wt % Additive 3009

TABLE 4 Chemical Name: Composition Solvent 1 70/30 by volume %PGME/PGMEA mix Solvent 2 Isopropyl alcohol Solvent 3 2-heptanone Solvent4 n-butyl acetate Solvent 5 water Solvent 6 PGME Solvent 7 propylenecarbonate Solvent 8 65/35 by volume % PGME/PGMEA mix Additive 1 Aceticacid Additive 2 Citric acid Additive 3 Oxalic acid Additive 42-nitrophenylacetic acid Additive 5 Dodecanoic acid Additive 62-ethylhexanoic acid Additive 7 ethylhexylphosphate Additive 8dihydroxyfumaric acid Additive 9 lactic acid Additive 10 triton-xAdditive 11 cyanoacetic acid

Example 2 Selected EBR Solvents and Fluorinated Acid Additives

This example demonstrates the effectiveness of organic solvents withfluorinated acid additives for performing effective bead edge rinsingwith tin based radiation patternable resists.

These experiments were performed using the tin based resist R1 andresist R2 noted in Example 1. The testing was performed as described inExample 1 with substitution of the fluorinated additives. All of thetesting in this example was performed with one 5 mL EBR rinse stagefollowed by 5×5 mL rinses with PGME/PGMEA solvent blend. The resultsobtained with R1 are presented in Table 5 and with R2 in Table 6. Thenotation N in the table represents equivalents per liter using standardnotation. These additives were particularly effective for the R2 resist.The solvents and additives for this Example are presented in Table 7.

TABLE 5 VDP-ICP Result Sn Wafer Strip Process Description (E10 atom/cm2)67 88 wt % Solvent 6 + 9 wt % Solvent 5 + 45 3 wt % Additive 12(Control-No resist) 68 Solvent 8 16000 69 83 wt % Solvent 10 + 17 wt %Additive 17 13 70 74 wt % Solvent 6 + 17 wt % Solvent 5 + 83 9 wt %Additive 14 71 68 wt % Solvent 11 + 24 wt % Solvent 5 + 30 8 wt %Additive 15 72 96 wt % Solvent 6 + 3 wt % Solvent 5 + 13 1 wt % Additive15 73 5 wt % Additive 16 + 95 wt % Solvent 6 28 with (w/) 2N Additive 16

TABLE 6 VDP-ICP Result Sn (E10 atom/ Wafer Strip Process Descriptioncm2) 74 60 wt % Solvent 6 + 30 wt % Solvent 5 + 0.77 10 wt % Additive 1575 60 wt % Solvent 6 + 30 wt % Solvent 5 + 6.3 10 wt % Additive 15 76 60wt % Solvent 6 + 30 wt % Solvent 5 + 8.1 10 wt % Additive 15 77 60 wt %Solvent 6 + 30 wt % Solvent 5 + 1.3 10 wt % Additive 15 78 80 wt %Solvent 6 + 15 wt % Solvent 5 + 14 5 wt % Additive 15 79 80 wt % Solvent6 w/1N Additive 17 + 2.8 15 wt % Solvent 5 + 5 wt % Additive 15 80 80 wt% Solvent 6 w/0.25N Additive 18 + 8.8 15 wt % Solvent 5 + 5 wt %Additive 15 81 80 wt % Solvent 6 w/0.5N Additive 18 + 19 15 wt % Solvent5 + 5 wt % Additive 15 82 80 wt % Solvent 6 w/1N Additive 18 + 20 15 wt% Solvent 5 + 5 wt % Additive 15 83 80 wt % Solvent 6 w/1N Additive 19 +3.2 15 wt % Solvent 5 + 5 wt % Additive 15 84 80 wt % Solvent 6 w/0.5NAdditive 16 + 6.3 15 wt % Solvent 5 + 5 wt % Additive 15 85 80 wt %Solvent 6 w/1N Additive 16 + 2.5 15 wt % Solvent 5 + 5 wt % Additive 1586 80 wt % Solvent 6 w/2N Additive 16 + 8 15 wt % Solvent 5 + 5 wt %Additive 15

TABLE 7 Chemical Name: Composition Solvent 5 water Solvent 6 PGMESolvent 10 PGMEA Solvent 11 propylene glycol Additive 12tetramethylammonium fluoride Additive 13 triethylamine•3HF Additive 14tetrabutylammonium•HSiF₆ Additive 15 hexaflourosilicic acid Additive 16tetrabutylammonium fluoride Additive 17 p-toluenesulfonic acid Additive18 sulfuric acid (H₂SO₄) Additive 19 benzenesulfonic acid

Example 3 Sacrificial Edge Under-Layer

This example demonstrates improved EBR processing based on theapplication of a sacrificial layer across the surface of the wafer.

A coating solution was applied to form sacrificial underlayer coatingsacross the entire wafer. The coating solutions comprised 5 wt %polystyrene dissolved in PGMEA and was applied to two wafer with twoadditional wafers being used as controls. In each case, a 5 mL quantityof the coating solution was dispensed onto a 100 mm wafer rotating at 50rpm. Immediately after the end of the dispensing process, the wafer wasspun at 1500 rpm for 45 s. Then, a 1.5 mL quantity of organo-tin basedresist solution R2 was dispensed over three wafers (the two edge coatedwafers and one control wafer) in a stationary position, and immediatelyafter the dispense of the resist solution, the respective wafer was spunat 1500 rpm for 45 s.

At the end of the wafer spin to spread the resist solution, the edgebead rinse (EBR) was performed as described in Example 1 and using 5cycles of rinsing with 5 mL of EBR rinse solution, except for thecontrol wafer without resist where no EBR rinse was performed. The EBRrinse solutions for the control wafer with resist but no edge coatingwas 65/35 vol % PGME/PGMEA, and for the wafers with sacrificial edgecoating, the EBR solvent was either PGMEA or 2-heptanone. Measurementswere performed to evaluate tin concentrations along the edges of the 4wafers, and the results are presented in Table 8. The edge coatingsignificantly improved the EBR process.

TABLE 8 VDP-ICP Result Sn Wafer Edge Coating EBR Solution (E10 atom/cm²)87 No None 12 88 No 65/35 Vol % 12000 PGME/PGMEA 89 Yes PGME 250 90 Yes2-heptanone 18

Example 4 Circumferential Anti-Adhesion Coating

This example demonstrates improved EBR processing based on theapplication of an anti-adhesion edge coating on the wafer.

A coating solution was applied to form anti-adhesion edge coatings. Thecoating solutions comprised 1 wt %poly(4,5-difluoro-2,2-bis(trifluoro-methyl)-1,3-dioxole-co-tetrafluoroethylene (FEO) dissolved in perfluorooctane (Solution 1) or intetradecafluorohexane (Solution 2). Solution 1 and Solution 2 wereapplied to separate wafers with two additional wafers being used ascontrols. To apply the coating solution, a 5 mL quantity of the coatingsolution was dispensed in an EBR apparatus along the edge of a 100 mmwafer rotating at 500 rpm. Immediately after the end of the dispensingprocess, the wafer was spun at 1500 rpm for 45 s. Then, a 1.5 mLquantity of organo-tin based resist solution R2 was dispensed over threewafers (the two coated wafers and one control wafer) in a stationaryposition, and immediately after the dispense of the resist solution, therespective wafer was spun at 1500 rpm for 45 s.

At the end of the wafer spin to spread the resist solution, the edgebead rinse (EBR) was performed as described in Example 1 and using 5cycles of rinsing with 5 mL of EBR rinse solution, except for thecontrol wafer without resist where no EBR rinse was performed. The EBRrinse solutions for the control wafer with resist but no coating was65/35 vol % PGME/PGMEA, and for the for a first wafer with sacrificialcoating EBR was PGMEA, and for wafers with an anti-adhesion edge coatingthe solvent used for EBR was the same as the solvent used for depositingthe coating solution. Measurements were performed to evaluate tinconcentrations along the edges of the 4 wafers, and the results arepresented in Table 9. The edge coating significantly improved the EBRprocess.

TABLE 9 VDP-ICP Result Sn Wafer Edge Coating EBR Solution (E10 atom/cm²)91 No None 12 92 No 65/35 Vol % 12000 PGME/PGMEA 93 1% FEO inperfluorooctane 380 perfluorooctane 94 1% FEO in tetradecafluorohexane740 tetradecafluorohexane

The embodiments above are intended to be illustrative and not limiting.Additional embodiments are within the claims. In addition, although thepresent invention has been described with reference to particularembodiments, those skilled in the art will recognize that changes can bemade in form and detail without departing from the spirit and scope ofthe invention. Any incorporation by reference of documents above islimited such that no subject matter is incorporated that is contrary tothe explicit disclosure herein. To the extent that specific structures,compositions and/or processes are described herein with components,elements, ingredients or other partitions, it is to be understood thatthe disclosure herein covers the specific embodiments, embodimentscomprising the specific components, elements, ingredients, otherpartitions or combinations thereof as well as embodiments consistingessentially of such specific components, ingredients or other partitionsor combinations thereof that can include additional features that do notchange the fundamental nature of the subject matter, as suggested in thediscussion, unless otherwise specifically indicated.

What is claimed is:
 1. A method of cleaning a substrate provided with ametal resist, the method comprising cleaning a substrate provided with ametal resist containing at least one metal selected from the groupconsisting of Sn, Hf, Zr, In, Te, Sb, Ni, Co, Ti, W, Ta, and Mo using ametal resist cleaning liquid comprising a solvent and a carboxylic acid,thereby removing the metal resist from the substrate.
 2. The methodaccording to claim 1, comprising applying the metal resist cleaningliquid along the periphery of the substrate to remove an edge bead onthe substrate.
 3. The method according to claim 1 wherein the organicsolvent comprises a propylene glycol methyl ether (PGME), propyleneglycol methyl ether acetate (PGMEA), propylene glycol butyl ether(PGBE), ethylene glycol methyl ether, cyclic esters, n-butyl acetate,ether acetate, ketones, liquid cyclic carbonates, or a mixture thereof.4. The method according to claim 1 wherein the amount of carboxylic acidbased on the total weight of the cleaning liquid is 0.1 wt % to 50 wt %.5. The method according to claim 3 wherein the amount of carboxylic acidbased on the total weight of the cleaning liquid is 0.1 wt % to 50 wt %.6. The method according to claim 1 wherein the metal resist contains Sn.7. The method of claim 1 wherein the carboxylic acid comprises formicacid and/or acetic acid.
 8. A method for removing edge bead on a waferassociated with a resist coating comprising a tin based resistcomposition, the method comprising: applying a first bead edge rinsesolution along a wafer edge following spin coating of the wafer with thetin organometallic resist composition, wherein the edge bead solutioncomprises an organic solvent and an additive comprising a carboxylicacid, an inorganic fluorinated acid, a tetraalkylammonium compound, or amixture thereof, wherein a residual tin measurement along the wafer edgeusing VPD-ICP-MS is no more than about 50×10¹⁰ atoms/cm², and whereinthe carboxylic acid comprises formic acid and/or acetic acid.
 9. Themethod of claim 8 wherein the tin organometallic resist compositioncomprises alkyl tin oxo/hydroxo moieties.
 10. The method of claim 8wherein the organic solvent comprises a glycol ether or ester thereof,an alcohol, a ketone, a cyclic ester, a liquid cyclic carbonate, or amixture thereof.
 11. The method of claim 8 wherein the organic solventcomprises a propylene glycol methyl ether (PGME), propylene glycolmethyl ether acetate (PGMEA), 2-heptanone, or a mixture thereof.
 12. Themethod of claim 8 wherein the additive further comprises acetic acid,citric acid, oxalic acid, 2-nitrophenylacetic acid, 2-ethylhexanoicacid, dodecanoic acid, ascorbic acid, tartaric acid, glucuronic acid,benzene sulfonic acid, p-toluenesulphonic acid, sulfuric acid (H₂SO₄),or a mixture thereof.
 13. The method of claim 8 wherein the first edgebead rinse solution comprises 0.1 wt % to 50 wt % formic acid.
 14. Themethod of claim 11 wherein the first edge bead rinse solution comprises0.1 wt % to 50 wt % formic acid.
 15. The method of claim 8 wherein thefirst edge bead rinse solution consists essentially of PGMEA and formicacid in a weight ratio of PGMEA:formic acid from 1:1 to 9:1.
 16. Themethod of claim 8 wherein the first edge bead rinse solution consistsessentially of PGMEA and acetic acid in a weight ratio of PGMEA:aceticacid from 1:1 to 9:1.
 17. A system for performing a bead edge removalcomprising: a spindle comprising a wafer support, wherein the spindle isoperably connected to a motor configured to rotate the spindle; a wafercomprising a surface layer of a tin organometallic resist composition; adispenser with a nozzle configured to apply fluid along an edge of thewafer mounted on the spindle; and a reservoir comprising a fluid,wherein the reservoir is configured to deliver the fluid to the nozzlefor dispensing, wherein the fluid comprises an organic solvent with anadditive comprising a carboxylic acid, a sulfonic acid, sulfuric acid(H₂SO₄), a phosphate ester, a phosphoric acid, an inorganic fluorinatedacid, a tetraalkylammonium compound, or mixtures thereof, wherein thefluid comprises the additive at a concentration from about 0.1 wt % toabout 25 wt %, wherein the carboxylic acid comprises formic acid and/oracetic acid.
 18. The system of claim 17 wherein the organic solventcomprises a glycol ether or ester thereof, an alcohol, a ketone, acyclic ester, a liquid cyclic carbonate, or a mixture thereof.
 19. Thesystem of claim 17 wherein the organic solvent comprises propyleneglycol methyl ether (PGME), propylene glycol methyl ethyl acetate(PGMEA), propylene glycol butyl ether (PGBE), ethylene glycol methylether, ethanol, propanol, isobutyl alcohol, hexanol, ethylene glycol,propylene glycol, 2-heptanone, propylene carbonate, butylene carbonate,or a mixture thereof.
 20. The system of claim 17 wherein the tinorganometallic resist composition comprises alkyl tin oxo/hydroxomoieties.